This invention relates to an endoscope for processing color information and providing a read-out signal that is fully compatible with any standard format television equipment.
In U.S. Pat. No. 4,074,306, there is disclosed an endoscope system for producing a full color image of the region scanned by the viewing head of the system. In this prior art device, the image information contained in the viewing region of the system is separated into the three primary colors of red, green and blue, and the images then sequentially laid down, one on top of the other, on a Braun tube to recreate the original full color image. The three primary color images are created by either mechanically filtering the illuminating light brought into the cavity using a single light source and a rotating filter disc or by breaking down a reflected light image of the viewing region using a series of dichroic mirrors.
Although the prior art device performs well, it nevertheless requires special equipment to sequentially process the three independent read-out signals. Mechanically driven filter discs also can present timing and balancing problems which, under certain conditions, can be troublesome. Because the disc mounted filters move through an arcuate path of travel, a sharp, well defined edge between images, which is essential in a high speed system, cannot be obtained. Lastly, the use of dichroic mirrors and the like in the viewing head of the system increases the size of the head and thus makes it difficult to insert into relatively small body cavities or openings thereby limiting the usefulness of the instrument.